what is difference between fork() and exec() system calls in operating system

  fork():
  • fork() starts a new process which is a copy of the one that calls it,
  • Both parent and child processes are executed simultaneously in case of fork()




 exec():


  •  exec replaces the current process image with another (different) one.
  • Control never returns to the original program unless there is an exec() error.

Comments

Post a Comment

Popular posts from this blog

Write C programs to simulate the Paging techniques of memory management

Image
#include<stdio.h> #define MAX 50 int main() { int page[MAX],i,n,f,ps,off,pno; int choice=0; printf("\nEnter the no of  peges in memory: "); scanf("%d",&n); printf("\nEnter page size: "); scanf("%d",&ps); printf("\nEnter no of frames: "); scanf("%d",&f); for(i=0;i<n;i++) page[i]=-1; printf("\nEnter the page table\n"); printf("(Enter frame no as -1 if that page is not present in any frame)\n\n"); printf("\npageno\tframeno\n-------\t-------"); for(i=0;i<n;i++) { printf("\n\n%d\t\t",i); scanf("%d",&page[i]); } do { printf("\n\nEnter the logical address(i.e,page no & offset):"); scanf("%d%d",&pno,&off); if(page[pno]==-1) printf("\n\nThe required page is not available in any of frames"); else printf("\n\nPhysical address(i.e,frame no & offset):%d,%d",page[pno],off); prin
Read more

Write C programs to simulate the Two level directory File organization technique

Write C programs to simulate the Two level directory File organization technique #include<string.h> #include<stdlib.h> #include<stdio.h> struct { char dname[10],fname[10][10]; int fcnt; }dir[10]; void main() { int i,ch,dcnt,k; char f[30], d[30]; dcnt=0; while(1) { printf("\n\n1. Create Directory\t2. Create File\t3. Delete File"); printf("\n4. Search File\t\t5. Display\t6. Exit\tEnter your choice -- "); scanf("%d",&ch); switch(ch) { case 1: printf("\nEnter name of directory -- "); scanf("%s", dir[dcnt].dname); dir[dcnt].fcnt=0; dcnt++; printf("Directory created"); break; case 2: printf("\nEnter name of the directory -- "); scanf("%s",d); for(i=0;i<dcnt;i++) if(strcmp(d,dir[i].dname)==0) { printf("Enter name of the file -- "); scanf("%s",dir[i].fname[dir[i].fcnt]); printf("File created"); break; } if(i==dcnt) printf
Read more

Write C programs to simulate the Hierarchical directory File organization technique

Write C programs to simulate the Hierarchical  directory File organization technique #include<stdio.h> #include<graphics.h> #include<string.h> struct tree_element { char name[20]; int x, y, ftype, lx, rx, nc, level; struct tree_element *link[5]; }; typedef struct tree_element node; void main() { int gd=DETECT,gm; node *root; root=NULL; create(&root,0,"root",0,639,320); clrscr(); initgraph(&gd,&gm,"c:\tc\BGI"); display(root); closegraph(); } create(node **root,int lev,char *dname,int lx,int rx,int x) { int i, gap; if(*root==NULL) { (*root)=(node *)malloc(sizeof(node)); printf("Enter name of dir/file(under %s) : ",dname); fflush(stdin); gets((*root)->name); printf("enter 1 for Dir/2 for file :"); scanf("%d",&(*root)->ftype); (*root)->level=lev; (*root)->y=50+lev*50; (*root)->x=x; (*root)->lx=lx; (*root)->rx=rx; for(i=0;i<5;i++) (*root)->li
Read more